This invention relates to methods of, and apparatus for, storing data signals, which data signals comprise radio frequency ultrasonic signals from an ultrasonic transducer and positional signals from a source associated with the transducer for subsequent reproduction.
Ultrasonic techniques and apparatus are employed in non-destructive testing, as is well known, the data signals received from ultrasonic transducers, being analogous to defects in the work piece being examined, may be displayed on a cathode ray oscilloscope or digitised and stored in a computer system. For storage of the signals whereby results of the examination can be pictorially re-displayed, it is known to record the pictorial representation of the oscilloscope display but unfortunately such recorded signals, which may have been processed before the original display, are dead precluding any further processing and are reproduced only with very poor resolution. Direct recording of the signals on magnetic tape is not practised because the high frequencies involved require excessive tape speeds and therefore large amounts of tape.
An object of the present invention is to provide a method of, and apparatus for, storing data signals from the ultrasonic transducers so that the signals can be reproduced in their original form and electronically processed where required.